Re: quarter wave

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Jared E Dwarshuis <jdwarshui-at-emich.edu> 

There was a question out there involving the location of current nodes.
  We were curious about this ourselves and produced a fully enclosed
primary for our prototype Saskia coil. Fully enclosed primaries do
function (at least for a full wave), but we saw no performance
advantage over multiple primaries. (multiple as in one primary per
current node). We elected to skip the second primary for our large
coil, it was already difficult loading the coil in the car and we
didn?t want to lose our portability.

We also noticed that for our prototype Saskia coil that we had a
localized heating of the primary directly above the current node, it
was narrow maybe two coil and very abrupt. We also found a mild warming
of the secondary at the current node, not abrupt at all. Observations
from our Marsha configuration indicate that the coils performs very
poorly with the primary off center by more then a few centimeters, or
with any non parallelism. Eccentricity of the primary with the
secondary had only a weak reduction in performance.  (a thermal image
would be instructive for analyzing resistive losses.)

It cost us less than 30 U.S dollars to make our Saskia coil prototype.
As far as coils go the prototype  is a piece of junk, it has tiny 28
gauge wires at screaming high frequencies, small sparks, a few inches
tops. But it did work, and that?s what we were looking for.

Honestly its not hard to make one of the prototype coils, don?t use to
small a wire or you will get crossovers, 28 gauge is as small a wire as
you would ever want to mess with. (my eyes got buggy after a few hours
of winding).  I would recommend sanding the foam form baby smooth with
some fine sand paper, then you can wind three or four turns fast and
loose and then tuck the winds closer together with your finger nail
while keeping just a bit of tension to pull up on the slack Wire
brushing while varnishing will fix up the spacing for the thin areas.
Hair splitting precision is not the way to go, it doubles the
frustration (and time) with no measurable improvement in performance.


What size do you want to build? If you just want to see the phenomena,
tiny works. If you want a good coil it will need to be very large. Our
Full size Saskia coils are 36? O.D. 20? I.D. we used 1415 meter 22
gauge at 212,000Hz. ( aprox. 9.3lb wire ). If we build another one it
will have 2804 meter wire at 107,000 Hz. We will keep the same 8? wind
diameter. ( foam comes in inches, hence the stupid units ) The coils we
have now are to small for comfort,  primary flashover to the voltage
nodes made us replace the old primary with a new close packed one just
for the extra clearance. With a bigger secondary  flashover would not
be a problem.

Mr. Nicholson:   We made no previous claims about properties of
materials per se, if an E.M. wave appears to travel slower than the
speed of light then you are not accounting for the actual path length.
Time delays in L.C. make perfect sense, but the shuffle of energy
between L and C and the velocity of waves along the wire are distinct
phenomena.  We will continue to look for evidence to support our
preliminary observations.  As far as inductance of the toroid, the
equations we gave, are the equations we used, and without any funkiness
at all when it came to tapping the primary for tuning, it was maybe an
1/8th  turn from the calculated position. (We used Wheeler for the
primary inductance as it accounts nicely for short solenoids).

Dying of curiosity, as to how you going to measure inter-node
inductance with this coil. Have you given any thought to the energy
storage mechanisms? We would like to know as well.  Also Mr. Nicholson,
some sympathy for the devil, we are not trying to be difficult about
data, if we had it, we would share it. We have neither your specific
training, nor your measuring tools. I hope that you can appreciate the
fact that we managed to do what we have done under difficult
circumstances, and with a leap of faith. I (Jared) made the coils in
the kitchen with a toddler tugging on my shirt, Larry and I both used
time and money that probably should have gone elsewhere.

  General advice for all coilers:

If you like to experiment don?t build museum coils. Make your parts
reusable and easy to replace. Blocks of Styrofoam and clear shipping
tape are not very glamorous but they do get the job done quickly and
they insulate very nicely. I do not know how hygroscopic Styrofoam is,
we seal the surfaces with varnish and clear tape where applicable.

Life is getting backlogged, so radio silence from us for a while.

Good Luck And Don?t Get Hurt!

-Jared and Larry